The objectives of the grant are to determine if heroin addicts differ from matched non-addict delinquents and non-addict, non-delinquents in terms of four "personality characteristics;" ability to delay gratification, susceptibility to peer pressure, level of social skills, and ability to express aggressive impulses. Four behavioral tasks have been developed to test the hypotheses. Task 1 asks the subjects to choose either a small, immediate reward or a larger, delayed reward; task 2 asks subjects to choose which of 4 lines matches a standard line after they have been given information about the choice of peers and non peers. Task 3 asks subjects to role play three drug related and three non-drug related scenes which are later rated for social skills such as fluency, eye contact, and overall assertiveness. Task 4 asks subjects to terminate a noise using either a punching bag or a push button while earning money by pulling a lever. Periods of earning money alternate with periods of extinction. Results from subjects who have participated in the first grant year indicate that the tasks are sensitive to the information required to achieve the objectives. Too few subjects have completed the tasks as of this writing to make statements about the differences between addicts and the two types of control subjects.